This invention relates to a device for writing and reading a two-dimensional scanning pattern. More particularly, it is concerned with a two-dimensional scanning device capable of obtaining a distortion-free light beam scanning image on the surface of a medium to be scanned.
This type of two-dimensional scanning device has been used in a laser beam printing apparatus which modulates the laser beam with image informations such as patterns, designs, characters, etc. from electronic computers and facsimile image transmitters, then subjects the modulated beam to a two-dimensional deflection, and produces high quality hard copies as an output at a high speed using the electrophotographic process or heat mode recording method, and others. It has also been used in an apparatus such as, for example, facsimile image transmitters, which deflects two-dimensionally an unmodulated laser beam, projects the thus deflected laser beam onto a two-dimensional pattern, and subjects light reflected from the pattern to photo-electric conversion to thereby obtain two-dimensional image informations. In the heretofore known two-dimensional scanning device, the scanning operation is performed on the scanning surface accompanying distortion. Correction of such distorted scanning pattern has been done electrically by the use of corrective operational circuits such as a position detector and a large-capacity memory device. Such electrical signal processing means, however, should unavoidably take a complicated construction.